Magnetic latching mechanism



July 19, 1966 F. e. ALESSI 3,261,631

MAGNETIC LATCHING MECHANISM Filed March 11, 1964 2 Sheets-Sheet l 32-" i f I I1 4 l3 4'3 Ti I INVENTOR. 591M 6: 44655/ July 19, 1966 F. G. ALESSI 3,261,631

MAGNETIC LATCHING MECHAI H SM Filed March 11, 1964 2 Sheets-Sheet z AWOQVEY United States Patent f 3,261,631 MAGNETIC LATCHING MECHANISM Frank G. Alessi, 1332 1st Ave., New York, N.Y. Filed Mar. 11, 1964, Ser. No. 351,022 7 Claims. (Cl. 292-2515) This invention relates to the art of latches and, more particularly, to a magnetic latching mechanism of improved construction and design.

The latching mechanism of this invention has wide application. It may be advantageously employed to releasably couple a movable structure in desired relative position to a stationary structure. The latching mechanism is especially useful to releasably maintain a door in open position and permit closing of the door upon applying a suitable force to the door or in response to predetermined ambient temperature conditions. Accordingly, the ensuing discussion and the detailed description that follows are directed, by way of example, to the use of my latching mechanism with a door.

It is frequently desirable to maintain a door in open position under normal use conditions. This is usually accomplished by means of a hook and eye arrangement and other mechanical devices. The latching mechanism of my invention permits a door to be readily swung to open position and automatically held in that position, as required. The door maybe conveniently swung to closed position by applying a suitable closing force which effects uncoupling of parts of the latching mechanism. To this end, the latching mechanism of this invention comprises a pair of units, one of which is secured to the door and the other to the floor or other stationary support. One of the units includes a permanent magnet and the other unit includes a magnetic member.

One of the features of the invention resides in the provision of a fusible element connecting parts of the unit which includes the magnetic member. The fusible member comprises a material, such as a suitable solder, which becomes plastic or molten when the ambient temperature exceeds a predetermined value. Thus, when the door is being held in open position by the latching mechanism and when the fusible element becomes molten due to a rise in temperature above normal, certain parts of the mechanism become disconnected. This allows the door to be swung to closed position by a spring or similar device known to the art. It will be apparent from the foregoing that the latching mechanism of this invention is especially useful with fire doors.

It is the primary object of this invention to provide an improved magnetic latching mechanism having novel features of construction and design.

Another object of the invention is to provide a magnetic latching mechanism which may be readily adjusted at the time of installation.

Another object of the invention is to provide an improved magnetic latching mechanism including a fusible element which permits disconnection of parts when the ambient temperature exceeds a predetermined value.

The invention has for a further object the provision of a magnetic latching mechanism having its parts so constructed and arranged as to minimize the possibility of tampering or removal by unauthorized persons after installation.

A still further object of the invention is to provide a latching mechanism of the character indicated that is sturdy and durable in construction; that is reasonable in manufacturing and installation costs; and that is capable of performing its intended functions in a satisfactory manner.

The enumerated objects and additional objects, together with the advantages of the invention, will be readily un- 3,251,631 Patented July 19, 1966 "ice derstood by persons trained in the art from the following detailed description and the accompanying drawings which respectively describe and illustrate a recommended magnetic latching mechanism embodying the invention.

In the drawings wherein like reference characters denote corresponding parts throughout the several views:

FIG. 1 is an isometric view of a latching mechanism of this invention cooperatively associated with a door and a floor;

FIG. 2 is a view similar to FIG. 1 and illustrates the units of the latching mechanism in another relative position;

FIG. 3 corresponds to FIG. 2 and shows certain parts in another relative position;

FIG. 4 is a view taken along staggered line 44 of FIG. 1;

FIG. 5 is a view taken along staggered line 5-5 of FIG. 4;

FIG. 6 is an exploded view of one of the units of the latching mechanism; and

FIG. 7 is an exploded view of the other unit of the latching mechanism.

Referring initially to FIGS. 1 and 2, I have illustrated therein a preferred form of magnetic latching mechanism M of this invention cooperatively associated with a door D and a floor F. The door is hinged at 10 to a side 11 of a door frame to permit swinging movement of the door about a vertical axis from open position (FIG. 1) to closed position. The door is equipped with suitable means (not shown) for normally and yieldingly urging the door in the direction of closed position about its hinged connection with the frame.

'Latching mechanism M consists of two units, namely a latch unit 12 and a catch unit 13 which will now be described.

Latch unit 12 comprises a floor plate 14 having a plurality of countersunk through openings 15 to receive screws 16 for firm attachment to floor F (FIG. 5). The floor plate is provided with a pair of taps 17 (FIG. 6). The latch unit also comprises a housing including a base 18 and an integral arcuate side wall 19. The base is formed with a bottom recess 20 to accommodate floor plate 14. The base plate is provided with a pair of countersunk through openings 21 anda plurality of taps 22. The base plate is firmly anchored to the floor plate by means of brass screws 23 which extend through openings 21 and engage taps 17. The housing also includes a cover 24 having an integral, depending, arcuate boss 25. Extending through cover 24 and .boss 25 are drill holes 26 which are axially aligned with corresponding taps 22 in base 18. Each hole 26 is drilled on two diameters so that its upper portion is large-r in diameter than its lower portion. Interposed between base 18 and cover 24 is a U- shaped permanent magnet 27 which terminates in end parts 27 and which defines an opening 28.

When the parts are assembled, boss 25 registers with magnet opening 28 and the end parts of the magnet extend slightly and beyond the housing, as best shown in FIG. 4. Cover 24 and magnet 27 are retained in place by brass screws 29 which extend through openings 26 and engage base taps 22.

In order to prevent tampering by unauthorized persons after unit 12 is installed, I provide plugs 30 which are inserted in the portions of drill holes 26 above screws 29. These plugs may be made of any suitable material and are preferably made of a material which may be readily drilled to permit access to screws 29 by authorized persons, as required.

All parts of latch unit 12, with the exception of magnet 27, :are made of non-magnetic metals. Floor plate :14 and the several parts of the housing are preferably made made of brass.

Catch unit 13 comprises a generally T-shaped bracket 31 consisting of a cross arm 32 and a bifurcated stem 33. Arm 32 has a pair of spaced through openings 34 and is formed with a recess 35. Stem 33 is provided with aligned openings 36, at least one of which is in the nature of a tap. The bracket has a tap 37 which communicates with recess 35 and the opening defined by stem 33. A set screw 38 engages tap 37. Bracket 31 is adapted to be secured to door D by means of screws 39 which extend through openings 34 (-FIG. 4).

The catch unit also comprises a bar member 40 which is made of a magnetic material, such as a suitable quality iron or steel, and a T shaped brass member 41 having an opening 42 and an arcuate edge portion 43. Bar member 40 and T-shaped member 41 are joined together by a fusible element 45. The fusible element comprises a suitable low melting composition which is solid at normal room temperatures "and which becomes plastic or molten at a predetermined elevated temperature, such as a temperature within the range of 130 F. to 145 F. Accord- I ingly, element 45 may be made of any appropriate solder composition having requisite properties and characteristics that is 'known to the art.

As is clearly shown in several views, member 41 projects in the opening defined by bifurcated stem 33 and is pivotally connected thereto by. a screw connector 46 which registers with openings 36 and 42. The angular position of members 40 and 41 relative to bracket 31 may be readily adjusted prior to attaching the bracket to the door by means of set screw 38. It is preferred to have the set screw inaccessible when the bracket is installed to minimize the possibility of tampering.

For the purpose of outlining the operation of the illustrated embodiment of the invention, it is assumed that the units :12 and -13 are assembled and respectively secured to floor F and door D, as shown in FIGS. 1 and 2. It is also assumed that door D is being swung in counterclockwise direction, and that units 12 and 13 are in the relative position shown in FIG. 2. A the door continues in a counterclockwise direction, unit 13 approaches unit 12 until magnetic unit 40 is engaged and held by permanent magnet 27 by magnetic attraction, as illustrated in FIG. 1. The door is maintained in this position under normal temperature conditions until such time as it is swung to closed position by applying a manual force to door D toward the left as viewed in FIG. 1. In the event the temperature in the room rises above a predetermined value, fusible element 45 becomes molten or plastic causing disengagement of magnetic member 40 from the remainder of unit 13 (FIG. 3). This allows the door to swing to closed position by the action of a spring or other door-closing device (not shown).

From the foregoing, it is believed that the construction, operation, objects and advantages of my present invention will be readily comprehended by persons skilled in the art without further description. It is to be clearly understood, however, that various changes in the construction described above and illustrated in the drawings may be made without departing from the scope of the invention, it being intended that all matter containedin the description or shown in the drawings shall be interpreted as illustrative only and not in a limiting sense.

I claim:

1. A latching mechanism for use with a support structure and a movable structure that is movable relative to the support structure, a first unit comprising a bracket that is adapted to be secured to one of said structures, a magnetic member, pivot means connecting the magnetic member to the bracket, and means comprising a locking member releasably connecting the bracket to the pivot means for adjusting the angular position of the magnetic member relative to the bracket, said first unit also including a fusible element that is solid at and below a preselected temperature and that becomes plastic at a temperature above said preselected temperature, said fusible element joining one portion of the first unit to the remainder thereof, and a second unit comprising a permanent magnet that is adapted to be secured to the other of said structures, the parts being so constructed and arranged that the first and second units are releasably coupled by magnetic attraction between the permanent magnet and the magnetic member when said structures are in one relative position. i

2. A latching mechanism according to claim 1 wherein the pivot means includes a connector member interposed between the magnetic member and the bracket and wherein the fusible element connects the magnetic member to the connector member.

3. A latching mechanism according to claim 1 wherein the second unit also comprises a housing including a base, a side wall and a cover and wherein the permanent magnet is at least partly positioned within the confines of the housing, the housing having its parts so configured and arranged as to maintain the permanent magnet in a predetermined position with respect thereto.

: 4. A latching mechanism according to claim 3 wherein the permanent magnet is U-shaped, the ends of the permanent magnet extending through the housing.

' 5. A' latching mechanism according to claim 1 wherein the pivot means includes a connector interposed between the magnetic member and the bracket, wherein the fusible element connects the magnetic member to the connector member, wherein the second unit also comprises a housing including a base,'a side wall and a cover and wherein the permanent magnet is at least partly positioned within the confines of the housing, the housing having its parts so configured and arranged as to maintain the permanent magnet in a predetermined position with respect thereto.

6. A latching mechanism according to claim 5 wherein the permanent magnet is U-shaped, the ends of the permanent magnet extending through the housing.

7. A latching mechanism according to claim 1 wherein the locking member comprises a set screw.

References Cited by the Examiner UNITED STATES PATENTS RICHARD E. MOORE, Examiner.

PATRICK A. CLIFFORD, Primary Examiner. 

1. A LATCHING MECHANISM FOR USE WITH A SUPPORT STRUCTURE AND A MOVABLE STRUCTURE THAT IS MOVABLE RELATIVE TO THE SUPPORT STRUCTURE, A FIRST UNIT COMPRISING A BRACKET THAT IS ADAPTED TO BE SECURED TO ONE OF SAID STRUCTURES, A MAGNETIC MEMBER, PIVOT MEANS CONNECTING THE MAGNETIC MEMBER TO THE BRACKET, AND MEANS COMPRISING A LOCKING MEMBER RELEASABLY CONNECTING THE BRACKET TO THE PIVOT MEANS FOR ADJUSTING THE ANGULAR POSITION OF THE MAGNETIC MEMBER RELATIVE TO THE BRACKET, SAID FIRST UNIT ALSO INCLUDING A FUSIBLE ELEMENT THAT IS SOLID AT AND BELOW A PRESELECTED TEMPERATURE AND THAT BECOMES PLASTIC AT A TEMPERATURE ABOVE SAID PRESELECTED TEMPERATURE, SAID FUSIBLE ELEMENT JOINING ONE PORTION OF THE FIRST UNIT TO THE REMAINDER THEREOF, AND A SECOND UNIT COMPRISING A PERMANENT MAGNET THAT IS ADAPTED TO BE SECURED TO THE OTHER OF SAID STRUCTURES, THE PARTS BEING SO CONSTRUCTED AND ARRANGED THAT THE FIRST AND AND SECOND UNITS ARE RELEASABLY COUPLED BY MAGNETIC ATTRACTION BETWEEN THE PERMANENT MAGNET AND THE MAGNETIC MEMBER WHEN SAID STRUCTURES ARE IN ONE RELATIVE POSITION. 